Concentration of ores



Patented dune l 7, 1 924.:

T-En M" n. sarnn, ornnw Rooi'afELLn, new Yam, assienoa'ro'mnrnns'nncovnnr COMPANY, OF YORK, N. Y., A. CORPORATION 015 IMAIIIN'E.v

concnn'rnarron or case.

No Drawin g.

To all whom it may concern/.5

. Be it known that l, RALPH E. SAYRE, a citizen of the United States,residing at New Rochelle, in the county of Westchester, 5 State of NewYork, have invented certain new and usefullmprovements intheConcentration of Ures; and I do hereby declare the followingto be afull, clear, and exact description of the invention, suchas will nenable others skilled in the art to which it appertains to-Inake and usethe same.

This invention relates to the concentra-. tion of ore minerals, and thelike, by flotation, and 11 2s for its object the provision of 15 certainimprovements in flotation processes, and :"IDOI'B particularly the frothflotation processes.

- The present invention is based upon the discovery that the salts ofsubstituted 2o dithiocarbamic acids are effective flotation reagents,particularly in non-acid or alkaline pulps. l have found that thesalts-of substituted dithiocarbamic "acids have a marked selectiveaction on sulfide minerals, as distinguished from gangue minerals, andwhen used as flotation agents in the customary flotation processes causethe sulfide mineral to'float'readily withan attendant high recovery ofthe metal "values. My investigations indicate that the salts ofsubstituted dithioc'arbamic acids are substantially lacking in .frothingpower, so that an appropriate frothing agent, such as pine-- oil,terpineol, or the like, should be' employed in conjunction therewith incarrying K out the flotation operation.-

The salts of substituted 'dithiocarbamic. acids (dithiocarbamates) maybe' prepared in accordance with well-known methods. In

40 general, the most convenient procedure for preparingsuchsaltsconsists in adding an alkali dissolved in alcohol to a mixture ofcarbodbisulfide and an amine. The aryl' dithiocarbamates (for example,potassium phenyldithioarbamate, C H NHS K) may be prepared in thismanner employing an arylamine. "In; preparing the alkyl dithiobarbamatesfor example diethylammonium .dieth ldit hiocarbamate tc no ncsmu (0 analkylamine may be dissolved in benzene and treated with carbonbisulfide.

In order to obtain the reaction product.

' in solid form, it is usually desirable to treat thereaction mixturewith ether or with some other solvent in which thedithiocarbasubstituted dithiocarbamic acids are in e 'carbamates (suchas the alkali and alkylties the aryl dithiocarbalnates are even morehave ound that the readily soluble dithio- Application filed Novemberas, 1923; serial-no. eraser),

mate is but slightly soluble. It is not necessary for the purposes ofthe-present invention to isolate thedithiocarbamate from the reactionmixture. Thus, in the practice of the present invention, thedithiocarbarnates may be used as crude reaction 'prdducts without beingisolated from the reaction mixture.

-.-The alkali and alkylammonium salts pit eral readily soluble in waterand alco ol. The heavy metalsalts (such as the lead, zinc, iron etc.salts) may be obtained as precipitates bytre'ating the dissolveddithioammonium dithiocarbamates) with a dissolved salt of the heavymetal. Thus, for example, lead-phenyl dithiocarbamate is pro duced bymixing solutions of lead acetate and potassium-phenyl dithiocarbamate.lln general, the heavy metal dithiocarbamates are only sparingly solubleeven in hot water.

I; have found that while the alkyl dithiocarbamates possess markedflotation propereffective 'fiotatiop agents, and for this reason Iprefer, in carrying out the present .invention, to use the arylcompounds.

In racticing the present invention, ll

carbamates give the best results when .introduced into {the flotationcircuit immediately before the flotation operation. The Same proceduremay be employed when. using the less-soluble dithiocarbamates, such astheheavy metal dithiocarbamates, the salts being dissolved in-hot waterbefore bein introduced- .into the flotation circuit. W en using theheavy metal dithiocarbamates I prefer, however,to add the sparingly'soluble.dithiocarbamates to the ore pulp prior to the final grindingoperation.

The quantity of the dithiocarbalnate fo be f employed in practicing thepresent invention 1 depends tosome extent upon the particular {00 saltbeing used and the particular ore being treated. In general, I havefound that onefifth ,of-a pound, and less, per ton of dry oregivessatisfactory results. v

I prefer to employ the dithiocarbamates' 05 as flotation agents in aneutral (that is nonacid) 'or' alkaline pulp. Any alkali, such ascaustic-soda, soda ash, orlinie, may be added to the ore pulp in orderto make the pulp neutral 'or alkaline. 'Lime, on the whole,

is the most suitable a'nd'available alkali for this purpose. The alkalishould'be'added to the-ore ulp before the final grinding.

' The thioca'rbamates' are of some value I as flotation. agents in acidtypical flotation results obtained in the practice' ofthe presentinvention. In all of the floats reported in this table, 500 grams of apartiallcyoground copper sulfide ore (of the Utah pper Company).assaying 1.34%

' copper were ground for twenty minutes-in a pebble mill with 250 c. c.of water and an amount of lime equivalent tofour pounds per'ton of dryore. The flotation operation wascarriedout in a laboratory size Callowrougher cell, after diluting-the ground ore pulp to'about 2.5 liters.The lead, iron and zinc dithiocarbamates were added to the ore pulp atthe start'of the grinding operation, while the potassiumdithiocarbamates were added after the grinding operation and immediately preceding the flotation operation. In each case] a drop of'theterpineol was added to the ore pulp immediately preceding flotation.

Amount I Cone. Tunings Recov- Reagem gf ggf copper. copper. cry

Potassium pnenylditnio- Pou nd. Per cent. Per cent. Per cent. carbamate0.2 14.5 0.28 80.8 Lead phenyldithiocarbamate U. 1 15. 5 0. 26 83. 2Potassium o-tolyldithiocarbamate 0.1 14.1 0.32 77; 9 Irono-tolyldithiocarbar .mate 0.1 15.6 0.30 79.1 Potassiuma-uaphthyldithiocarbamate 0. 1 15. 3, 0. 29 80. 1 Zinc .anaphthyldithi.carbamatc' 0. 1 18. 4 0. 33 76. 8

It will be'understood by those skilled in j the art that the prese'ntinvention is applia cable to the treatment by flotation of various kindsof mineral mixtures both natural and artificial. In the appended claimsI have accordin ly employed the terms mineral' and ore 1n abroad sense'to include'ores,

mineral'products. and all materials amenable to concentration or similartreatment'by the flotation processes.

Iclaimz I 1. The improvementin the concentration of minerals byflotation which comprises subjecting the mineral in the form of a pulp.

to a'flotation operation in the presence of a dithiocarbamate.

' 2. The improvement in the concentration of minerals by flotation whichcomprises subjecting the mineral in the form of a pulp to a flotationoperation, in the presence of an aryl dithiocarbamate.

3. Th -improvement in the concentration of minerals by flotation whichvcomprises subjecting the mineral in'the form of a nona cid pulp to aflotation operation in the presence of a dithiocarbamate.

4. The improvement in the concentration of minerals by flotation whichcomprises subjecting the mineral in the form of a nonacid pulp to aflotation operation in the presence of anaryl dithiocarbamate;

5. The improvement in the concentration of mineralsby flotation \vhichcomprises subjecting the'mineral in the form of an alkaline pulp toaflotation operation in'the presence of a dithiocarbamate.

6. The improvement in the concentration of minerals; by flotation whichcomprises subjecting the mineral in the form of an alkaline pulp to aflotation operation in the presence of an aryl dithiocarbamate.

7. The improvement in the concentration of minerals by flotation whichcomprises subjecting the mineral in the form of a pulp made alkaline bythe addition of lime to a flotation operation in the presence of an aryldithiocarbamate.

8. The method of concentrating ores and the like which comprisessubjecting the ore in the form of a suitable pulp to a flotationoperation in the presence of a salt of a sub-' stituted dithiocarbamicacid.

9. The method of concentrating ores and the like which comprisessubjecting theore in the form of a suitable pulpto a flotation operationin the presence of a salt of a substituted dithiocarbamic acid whichsalt is only sparingly soluble in water the like which consistsinsubjecting the ore in the form of a suitable pulp to a flotation 10.The method of concentrating ores and" I operation .in the. presenceof aheavy metal ,salt of asubstituted dithiocarbamic acid.

11; The method of concentrating ores and the like which consistsinlsubjecting the ore in the form of a suitable .pulp to a flotation ooration in the presence of lead. phenyldit iocarbamate.

In'testimony whereof I aflix my si nature.

RALPH E. SA; RE;

